Power transmission

Abstract

A speed controller for a rotary pump and motor hydraulic power transmission comprises a pair of pulse generators, one driven at a reference speed and the other proportionally to motor speed. An algebraic summing circuit connects the two pulse generators to the displacement regulator of the hydraulic pump. Error signals produced by the changes in phase of the pulse generators adjust the pump displacement to maintain the motor speed in step with the reference speed.

I claim: 
     
       1. A speed controller for a hydraulic power transmission comprising a rotary pump and a rotary motor, one of which has a regulator for its displacement, the controller comprising a reference hydraulic pulse generator for producing an alternately reversing flow of a predetermined quantity, a feed-back pulse generator for producing another alternately reversing flow of a similar quantity, reference means for driving the reference pulse generator at a desired speed, means driving the feed-back pulse generator proportionally to the motor speed, and a circuit connecting the two pulse generators to the displacement regulator, to maintain the motor speed in step with the reference means speed in response to error signals produced by relative phase changes between the two pulse generators. 
     
     
       2. A speed controller as defined in claim 1 wherein the circuit of the controller includes a one-way connection between the pulse generators and a second one-way connection from the pulse generators to the displacement regulator with a constant flow bleed path from the regulator. 
     
     
       3. A speed controller as defined in claim 2 which includes means replenishing either of the pulse generators whenever it is out of phase with the other one. 
     
     
       4. A speed controller as defined in claim 1 wherein the regulator varies the pump displacement. 
     
     
       5. A speed controller as defined in claim 1 wherein the circuit of the controller includes means for feeding the delivery of one pulse generator to the regulator and means for algebraically summing the delivery of the two pulse generators for comparison with a constant bleed from the regulator.